Comotomo Baby Bottles feature innovative and sensible design to most closely mimic natural breastfeeding. It is naturally shaped, soft, silicone nipples. Ideal for babies who have trouble transitioning from nursing to bottle feeding. The bottles are equipped with truly innovative vents that are smartly designed to prevent colic, while completely eliminating annoying leaks. They are quite possibly the most thoughtful bottles ever made. 250ml/5 ounce bottles come with slow flow nipples (1 hole) ideal for 0-3 months.